As is well known, the conventional type of tennis racquet is strung in a rectilinear or x-y configuration, with numerous strings being parallel to each other, and perpendicular to a parallel array of vertically disposed strings. The horizontal and vertical strings define an open mesh in which substantially all of the holes are square.
Because the head of the conventional racquet is oval, only three or four horizontal strings and only three or four vertical strings are full length strings extending across the racquet frame. The area bounded by these full length strings is often referred to as the "sweet spot" by the tennis buff.
A dynamic analysis has shown that regardless of where the ball is struck with a conventional racquet, only three or four strings in each direction transfer the shock load of the rapidly moving ball to the frame, and the frame is caused to deflect inward at these four locations where the strings are anchored. This inward deflection of these frame portions necessarily brings about a relaxing of the initial tension applied to these strings, and the other strings of the racquet not only fail to compensate for this, but also if anything they contribute to such condition because of their preload.
Another consequence of having a racquet strung in the conventional rectilinear manner is that the farther away from the center of the racquet that the ball is struck, the shorter the effective length of the strings, and this causes a faster response of the shock from the racquet to the player's arm. It is therefore apparent that if all of the strings of the racquet could react equally, such would minimize the shock to a player's arm.